import java.util.Map;
import java.util.Set;

public class Test03 {
    public static void main(String[] args) {
        Map<String,String> map=Map.of("张三","北京","李四","江苏","王五","上海");
        Set<String>  keys=map.keySet();
        for(String key:keys){
            String value=map.get(key);
            System.out.println(key+"="+value);
        }
        Map<String,String> m=Map.copyOf(map);
        System.out.println(m);

    }
}
